Janus and Magus can't be the same person. Let me explain.
Schala = Kino. Since Schala and Janus were siblings, this means they must have been sent to the same time period. Magus came from 600 AD, so he can't be Janus, since Janus was sent with Schala/Kino to 65 million BC.
So what hapenned to Janus? Simple. He's Ayla. And you may be asking, "Well Ayla's a girl, how can this be?" Simple. Ayla is obviously more manly than her husband, Kino, who is actually quite girly. Which makes perfect sense, because Schala IS kino!
So, explain to me, if Janus is really Ayla, how Janus could possibly be Magus?